The Italians were the first army ever to adopt a sub-machine gun, or more correctly, a light automatic gun firing a pistol cartridge. This was the Villar Perosa that ceased to be a service weapon in 1918. The mechanism of the VP was a sound design and shortly after the end of the war the manufacturers of the VP were asked to produce a more practical weapon that became known as the OVP.
Kinda difficult to find detailed pictures to build this one but the result seems ok.
April 2017